Evaluate a Piecewise Function

Consider the function defined by the piecewise function:

$f(x) = \begin{cases} 2x + 3 & \text{if } x < 1 \\\ 5 & \text{if } x = 1 \\\ x^2 - 1 & \text{if } x > 1 \end{cases}$

Determine the value of $f(f(0))$.